Automatic winding mechanism for watch movements

ABSTRACT

An automatic winding mechanism for a watch movement with a unidirectional clutch comprising a cup-shaped wheel having inner and outer teeth, an element movable within the wheel transverse to the axis of rotation for transferring the winding weight to the inner teeth of the cup-shaped wheel.

July 8, 1975 58/82 A X 58/82 A 2,765,679 10/1956 3,838,567 10/1974 Giger et AUTOMATIC WINDING MECHANISM FOR WATCH MOVEMENTS FOREIGN PATENTS OR APPLICATIONS 331,124 6/1958 Switzerland..l................,.l... 58/82 A [75] Inventors: Josef Fliick; Roland Zaugg, both of Grenchen, Switzerland [73] Assignee: A. Schild S.A., Grenchen,

Switzerland Primary ExaminerGeorge H. Miller, Jr. Attorney, Agent, or Firm-Stevens, Davis, Miller & Mosher [22] Filed: Nov. 14, 1974 [2]] Appl. No.2 523,749

ABSTRACT [30] Foreign Application Priority Data Nov. 21, 1973 Switzerland........,.......

6357/73 An automatic winding mechanism for a watch movement with a unidirectional clutch comprising a cup- [52] US. 58/82 R Int. Cl. G04b 5/02 shaped whee] having Inner and outer teeth an elemem movable within the wheel transverse to the axis of ro- [58} Field 58/82 82 A; 235/105 tation for transferring the winding weight to the inner teeth of the cup-shaped wheel.

[56] References Cited UNlTED STATES PATENTS 10 Claims, 3 Drawing Figures 2,752,751 7/1956 Vaucher 58/82 A PKTENTED JUL 8 I975 3.893290 SHEET 1 PATENTED L 3 SHEET N OE AUTOMATIC WINDING MECHANISM FOR WATCH MOVEMENTS This invention relates to an automatic winding mechanism for watch movements. comprising a support. an arbor pivotingly mounted on the support. a winding weight integral with the arbor. a winding gear-train. and a unidirectional clutch device coaxial with the arher, the first gear of the gear-train being a reduction gear. and the clutch device connecting the arbor to the reduction gear so as to drive the gear-train when the weight rotates in a predetermined direction.

Winding mechanisms of this kind are already known. They present the particularity that the movements of the winding weight are utilized to wind the mainspring only when the weight moves in a certain direction. whereas the weight idles when it rotates in the opposite. non-winding direction. Although mechanisms of this kind have been known for many years now. it was long thought preferable to construct mechanisms equipped with a reverser instead of the unidirectional clutch in order to utilize the movements of the weight regardless of their direction. The development of winding mechanisms with unidirectional clutches was not pursued. and the undirectional clutches of winding mechanisms winding in only one direction still present numerous drawbacks. In particular. these known mechanisms comprise coupling members with resilient tongues which exert axially directed forces upon the arbor of the winding weight. and this tends to brake the movements of the weight. Moreover. the reliability of these known clutches leaves something to be desired.

It has recently been realized that automatic winding mechanisms winding in only one direction and equipped with a unidirectional clutch coaxial with the arbor are sufficiently effective for winding the mainspring and are. at the same time. simple and robust. thus making it possible to reduce the cost price of the winding mechanisms while ensuring that the automatic winding operation is carried out perfectly well. However. the use of such an arrangement has necessitated the provision of a reliable and compact unidirectional clutch with good efficiency.

The object of the present invention is therefore to provide an automatic winding mechanism of the type which winds in only one direction and which is equipped with such a unidirectional clutch.

To this end. in the automatic winding mechanism according to the present invention, the support comprises two parallel elements guiding the arbor at two different levels. and the unidirectional clutch device comprises, disposed between the support elements, a wheel mounted loose on the arbor and having a cupped portion, an outer toothing. and an inner toothing. and a bolt which is situated in the cupped portion. is integral in rotation with the arbor. and is adapted for translatory motion perpendicular to the axis of the arbor. the bolt cooperating with the inner toothing to make the arbor and the wheel integral upon rotation of the winding weight in the predetermined direction.

Furthermore, it is known that in order to keep the mainspring ofa watch movement wound. it is necessary to provide a blocking member which allows the barrelarbor to rotate in the winding direction but blocks it in the unwinding direction. Mechanisms of various forms have already been used for this blocking device, e.g.. a click-pinion having a toothing shaped in such a way as to block the ratchet-wheel integral with the barrelarbor when the ratchet-wheel tends to rotate in the unwinding direction. but allowing rotation in the winding direction. Devices have likewise been proposed which comprise a bolt mounted on the barrel-arbor and moving transversely under the influence ofcentrifugal force when the arbor tends to rotate. The latter devices were abandoned long ago. however. and only the click devices are currently used.

In one embodiment of the present invention. the retaining device for the barrel-arbor comprises a clickpinion which cooperates with the wheel-toothing of one of the gears. preferably the first one. of the multiplying gcar-train of the automatic winding mechanism.

A preferred embodiment of the invention will now be described in detail with reference to the accompanying drawings. in which:

FIG. I is a top plan view of the mechanism.

FIG. 2. is a section taken on the line I||I of FIG. I.

and

FIG. 3 is a section taken on the line III-III of FIG.

The automatic winding mechanism illustrated in the drawings is designed to be manufactured and mounted as a self-contained assembly which may be fitted as a single unit on the back surface of a watch movement. Part of this watch movement is shown in FIG. 2, where a frame element I is visible. constituting a wheel-train bridge. for example. The drawing also shows a ratchetwheel 2 which is integral with a barrel-arbor as in any conventional watch movement. The automatic winding assembly comprises a support formed of two bridges 3 and 4 which are mutually adjusted by means of two pins 5 and 6 and secured to one another by a screw 7 passing through the bridge 4 and the thickest portion of the bridge 3. The pins 5 and 6 are driven into the bridge 4 and engaged without play in corresponding openings in the bridge 3. They project out of the bridge 4 so as to be able to engage in openings 8 in the bridge I. thus ensuring the proper positioning of the assembly on the movement. The assembly is secured by means of two screws 9. the heads of which are countersunk in recesses in the outer surface of the bridge 3.

The ratchct-wheel 2 is automatically wound by means of a rotary weight I0, a portion of which is shown in FIG. 2. The weight I0 is integral in rotation with an arbor II, to which it is secured by means of a rigid disc 12 and a resilient disc 13. The resilient disc 13 has a circular central opening; it is engaged in a circular recess in the winding weight 10 and around a protruding head of the arbor II and is held in place by the rigid disc 12, which has a keyhole-shaped opening engaging under the protruding head of the arbor II and being blocked under that head.

Thus the weight 10 and the arbor 11 are rigidly con nected as long as the torque exerted by the weight I0 does not exceed a given limit. When that limit is reached. the weight 10 can slide beneath the resilient disc 13, thus protecting the transmission mechanism. As a variation. however. any other rigid fixing means might be provided between the weight I0 and the arbor II which would cause the arbor II to rotate when the weight 10 moves owing to its heaviness or inertia. A cylindrical bearing surface 14 of the arbor II pivots in a circular opening in the thinnest portion of the bridge 3, and a pivot-shank 15 at the end of the arbor ll remote from the weight pivots in a corresponding opening in the bridge 4.

The movements of the oscillating weight 10 and of the arbor 11 are transmitted to the ratchet-wheel 2 by a gear-train comprising a first wheel-and-pinion 16 coaxial with the arbor 11. This wheel-and-pinion consists of a pinion 17, engaged on a cylindrical bearing surface 18 of the arbor 11, and a ring-wheel 19 which has an inner toothing 19a and is secured to the pinion 17. The inner toothing 19a has an odd number of slightly spaced triangular teeth, as may be seen in FIG. 1. The pinion 17 meshes with the wheel of a speed-reducer wheel-and-pinion 20 which pivots between the bridges 3 and 4, and the pinion of which is engaged with the wheel of a wheel-and-pinion 21. The latter pivots on a fixed pin 22 driven into an opening in the bridge 3 and is held in place axially by an annular rib 23 stamped in the inner surface of the bridge 4 coaxially with the pin 22. The bridge 4 also has a circular opening 24 within the rib 23 so that the pinion of the wheel-and-pinion 21 and the end of the pin 22 can project out of the assembly in such a way that the toothing of the pinion of the wheel-and-pinion 21 meshes with the ratchet-wheel 2. The wheel of the wheel-and-pinion 20 cooperates with a retaining click-pinion 29 (FIG. 3), the teeth of which are engaged with that wheel. The click-pinion 29, which has an asymmetrical toothing, pivots on a stud 30 projecting from the inner surface of the bridge 3. It is held in place between the bridges 3 and 4 and protrudes into respective openings 31 and 32 in these bridges, the first opening constituting an inspection hole and the second an oiling hole.

In the embodiment illustrated in the drawings, the asymmetry of the teeth of the pinion 29 is such that if the wheel of the wheel-and-pinion 20 rotates counterclockwise, as viewed in FIG. 1, two adjacent teeth of the pinion 29 simultaneously come in contact with two adjacent teeth of the wheel 20, and the gearing is blocked by the pressure of the apex of one of the teeth of the click-pinion 29 on the arcuate apex of one of the teeth of the wheel 20. It will be noted that the arcuate apices of these teeth all lie on the circumference of a circle coaxial with the wheel 20. If the wheel 20 rotates clockwise, the relative positioning of the wheel 20 and the click-pinion 29 changes because their respective toothings are engaged with a relatively substantial amount of play. It is then the convex edge of a tooth of the click-pinion 29 which is pushed by the flank of a tooth of the wheel 20. Blocking is no longer possible, and the click-pinion 29 is driven rotatingly. It will likewise be noted that in this embodiment of the click system, the teeth of the wheel 20 are symmetrical. Moreover, the use of the click-pinion described makes it possible to eliminate the click-spring which would be indispensable with a conventional retaining device.

For the purpose of driving the ratchet-wheel 2 from the arbor 11 when the latter rotates in a predetermined winding direction, the mechanism described here further comprises a unidirectional clutch device between the pinion l7 and the arbor 11. The elements of this clutch device are as follows: the lower portion of the bearing surface 18 has two parallel flat portions 25, so that its cross-section through a plane perpendicular to the arbor 11 has the shape of a rectangle with rounded ends. As may be seen in FIG. 2, the flat portions 25 are on the same level as the inner toothing 19a of the ringwheel 19. interposed between the flat portions 25 and the toothing 19a is a bolt 26 consisting of an elongated flat plate blanked in the shape of a rectangle with rounded ends and having two beaks 27 and 28, directly opposite one another and projecting outwardly from the respective centers of the two rounded ends. The bolt 26 also has a central opening comprising two straight edges, the space between them being equal in width to the distance between the two flat portions 25, and the length of the space being greater than the diameter of the bearing surface 18. The ends of the two straight edges are joined by edges having the shape of arcs of a circle with a slightly greater radius than that of the bearing surface 18, so that the bolt 26 can move transversely to the axis of the arbor 11 until one or the other of the ends of its opening comes up against the bearing surface 18. Moreover, as the width of this opening is adjusted to the distance between the flat portions 25, the bolt 26 and the arbor 11 are rotatingly coupled. As for the beaks 27 and 28, their dimensions are such that, whatever the position of the bolt 26, one of them is engaged with the toothing 190.

Therefore, as may be seen in FIG. 1, if the winding weight rotates clockwise, the bolt 26 oscillates on the bearing surface 18, for the beaks 27 and 28 are alternately pushed away by the backs of the teeth 19a. Thus the wheel-and-pinion 16 is not driven, for like the wheels-and-pinions 20 and 21, it is blocked by the click-pinion 29. The gear-train being blocked, the weight idles. As soon as the weight rotates counterclockwise, on the other hand, one of the beaks 27 or 28 hooks into the radial flank of one of the teeth 19a, so that the wheel-and-pinion 16 and the arbor 11 are coupled. The pinion 17 drives the wheel-and-pinion 20 clockwise. The pinion of the wheel-and-pinion 20 drives the wheel of the wheel-and-pinion 21 counterclockwise, so that the ratchet-wheel 2 is driven clockwise, the ratio of reduction between the speeds of rotation of the weight and the ratchet-wheel, respectively, being about 1:150. It will be noted that the ratchetwheel 2 is likewise equipped with a conventional retaining click which prevents the mainspring from upwinding.

When the mainspring is wound by hand, the ratchetwheel 2 is driven by a crown-wheel (not shown). The wheels-and-pinions 21 and 20 are likewise driven rotatingly, as is the wheel-and-pinion 16. The direction of rotation of the latter wheel-and-pinion is such that the bolt 26 effects an oscillating movement in its plane, i.e., perpendicular to the axis of the arbor 1 1. Because of its great inertia, the winding weight does not move.

The winding mechanism described above presents numerous advantages. It is made up of elements which, like the bridges 3 and 4 and the various wheels and pinions described, may be easily machined. It will be noted in particular that all the holes in the bridges are circular ones, which considerably facilitates blanking. Moreover, the mechanism does not include any springs, and this simplifies manufacture by eliminating all the operations involved in the production of resilient blades having to conform to specified tolerances, as well as their inspection and testing. What is more, owing to these particularities, the mechanism is very easy to assemble. These operations are especially simplified by the fact that the springs comprised by the previously-known mechanism have been eliminated. The elimination of the springs also makes possible an improvement in the mechanical efficiency of the transmission. Finally, be-

cause the unidirectional clutch device of the mechanism described is mounted coaxially with the arbor ll, its size may be such that it operates reliably and is resis tant to wear without its taking up too much space with respect to the rest of the mechanism.

A last advantage of the mechanism described here is that the automatic winding assembly a whole is completely independent of the basic caliber. It thus enables the manufacture of movements to be carried out more efficiently by creating groups of related calibers. A basic caliber without automatic winding may be transformed into an automatic-winding movement simply by adding the assembly, without making any changes in the rest of the movement.

What is claimed is:

1. An automatic winding mechanism for watch movements, comprising a support. an arbor pivotingly mounted on said support, a winding weight integral with said arbor, a winding gear-train. and a unidirectional clutch device coaxial with said arbor. the first gear of said gear-train being a reduction gear, and said clutch device connecting said arbor to said reduction gear so as to drive said gear-train when said weight rotates in a predetermined direction, wherein said support comprises two parallel elements guiding said arbor at two different levels, and said clutch device comprises. disposed between said elements, a wheel mounted loose on said arbor and having a cupped portion. an outer toothing, and an inner toothing, and a bolt which is situated in said cupped portion, is integral in rotation with said arbor, and is adapted for translatory motion perpendicular to the axis of said arbor. said bolt cooperating with said inner toothing to make said arbor and said wheel integral upon rotation of said weight in said predetermined direction.

2. A winding mechanism in accordance with claim 1, wherein said arbor comprises a projecting collar and an annular shoulder which determine the axial position of said arbor between said elements, and said wheel is axially held in place by said collar and by an inner surface of one of said elements.

3. A winding mechanism in accordance with claim 1, further comprising a unidirectional blocking device which acts upon a toothing of a gear of said gear-train.

4. A winding mechanism in accordance with claim 3, wherein said blocking device comprises a click-pinion having an asymmetrical toothing engaged in said toothing of a gear and so disposed that two of its teeth block said gear by butting upon rotation of said gear in one direction. whereas said click-pinion is rotatingly driven upon rotation of said gear in the opposite direction.

5. A winding mechanism in accordance with claim 1. wherein said arbor and the gears of said gear-train are borne by said elements. and said elements are secured to one another and constitute an assembly. said assembly comprising means for positioning it upon and securing it to a watch movement.

6. A winding mechanism in accordance with claim 5, wherein the last gear of said gear-train comprises a pinion projecting out of said assembly and adapted to mesh with a ratchet-wheel when said assembly is positioned upon said watch movement.

7. A winding mechanism in accordance with claim 1. wherein said inner toothing is a wolf-tooth toothing. and said bolt comprises two beaks. each said beak being situated at a respective end of said bolt. said beaks cooperating alternately with said inner toothing.

8. A winding mechanism in accordance with claim 7, wherein said inner toothing comprises an odd number of teeth.

9. A winding mechanism in accordance with claim 7, wherein said bolt consists of a flat plate having an elongated opening, and said arbor comprises a bearing surface having two flat portions on which said opening is engaged and which drive said bolt rotatingly. the width of said opening being greater than the diameter of said bearing surface.

10. A winding mechanism in accordance with claim 9, wherein said opening comprises two straight. parallel edges and two arcuatc end edges defining a space. the width of said space being equal to the distance between said flat portions. and the arcs defining said end edges being arcs of a circle having a radius greater than that of said bearing surface. 

1. An automatic winding mechanism for watch movements, comprising a support, an arbor pivotingly mounted on said support, a winding weight integral with said arbor, a winding gear-train, and a unidirectional clutch device coaxial with said arbor, the first gear of said gear-train being a reduction gear, and said clutch device connecting said arbor to said reduction gear so as to drive said gear-train when said weight rotates in a predetermined diRection, wherein said support comprises two parallel elements guiding said arbor at two different levels, and said clutch device comprises, disposed between said elements, a wheel mounted loose on said arbor and having a cupped portion, an outer toothing, and an inner toothing, and a bolt which is situated in said cupped portion, is integral in rotation with said arbor, and is adapted for translatory motion perpendicular to the axis of said arbor, said bolt cooperating with said inner toothing to make said arbor and said wheel integral upon rotation of said weight in said predetermined direction.
 2. A winding mechanism in accordance with claim 1, wherein said arbor comprises a projecting collar and an annular shoulder which determine the axial position of said arbor between said elements, and said wheel is axially held in place by said collar and by an inner surface of one of said elements.
 3. A winding mechanism in accordance with claim 1, further comprising a unidirectional blocking device which acts upon a toothing of a gear of said gear-train.
 4. A winding mechanism in accordance with claim 3, wherein said blocking device comprises a click-pinion having an asymmetrical toothing engaged in said toothing of a gear and so disposed that two of its teeth block said gear by butting upon rotation of said gear in one direction, whereas said click-pinion is rotatingly driven upon rotation of said gear in the opposite direction.
 5. A winding mechanism in accordance with claim 1, wherein said arbor and the gears of said gear-train are borne by said elements, and said elements are secured to one another and constitute an assembly, said assembly comprising means for positioning it upon and securing it to a watch movement.
 6. A winding mechanism in accordance with claim 5, wherein the last gear of said gear-train comprises a pinion projecting out of said assembly and adapted to mesh with a ratchet-wheel when said assembly is positioned upon said watch movement.
 7. A winding mechanism in accordance with claim 1, wherein said inner toothing is a wolf-tooth toothing, and said bolt comprises two beaks, each said beak being situated at a respective end of said bolt, said beaks cooperating alternately with said inner toothing.
 8. A winding mechanism in accordance with claim 7, wherein said inner toothing comprises an odd number of teeth.
 9. A winding mechanism in accordance with claim 7, wherein said bolt consists of a flat plate having an elongated opening, and said arbor comprises a bearing surface having two flat portions on which said opening is engaged and which drive said bolt rotatingly, the width of said opening being greater than the diameter of said bearing surface.
 10. A winding mechanism in accordance with claim 9, wherein said opening comprises two straight, parallel edges and two arcuate end edges defining a space, the width of said space being equal to the distance between said flat portions, and the arcs defining said end edges being arcs of a circle having a radius greater than that of said bearing surface. 